1. Field of the Invention
The present invention relates generally to the field of lubricating and cooling components of vehicle engines and more particularly to a new and useful device for supplying post-shutdown coolant to a turbocharger.
2. Brief Description of the Prior Art
The impeller in a turbocharger is driven by the high-temperature exhaust stream from an internal combustion engine. During operation, at very high rpm, the bearings in the turbocharger receive lubricating and cooling oil from the engine's oil pump.
When the engine is shut off, the impeller has a considerable run-down time when it is coasting without receiving oil from the oil pump. During run-down, the high temperatures in the turbocharger quickly dissipates any residual oil in the impeller bearings resulting in a short turbocharger life.
Prior art known to applicant comprises the following United States Patents:
Robinson, U.S. Pat. No. 1,495,715; PA1 Moore, U.S. Pat. No. 1,562,037; PA1 Florence, U.S. Pat. No. 2,888,098; PA1 Haworth et al., U.S. Pat. No. 2,930,188; PA1 Kofink et al., U.S. Pat. No. 3,138,221; PA1 Rust, U.S. Pat. No. 3,827,236; and PA1 Capriotti, U.S. Pat. No. 4,157,744.
Capriotti U.S. Pat. No. 4,157,744 discloses a device for automatically supplying both pre-lubrication and post-shutdown cooling lubrication to a turbocharger. The device features bleeding oil from the main oil supply line during engine operation to fill a pair of tanks with oil under piston compression. Upon engine shutdown, a control valve opens to permit cooling oil to flow from one tank to the turbocharger. Upon recranking another valve opens to permit flow of pre-lubricating oil from the second tank to the turbocharger.
Robinson U.S. Pat. No. 1,495,715 shows a piston having a tailrod which serves as a valve member.
Rust U.S. Pat. No. 3,827,236 discloses a cooling system for turbochargers including an auxiliary pump and conduits bypassing the engine oil pump, the auxiliary pump being controlled in its operation by both a temperature-responsive device in the turbocharger and a low-or-no-pressure responsive device.
Kofink et al, U.S. Pat. No. 3,138,221 discloses a device for supplying oil to a turbocharger during start-up. In one embodiment of this invention, oil is accumulated in a bellows which is held against the force of a strong spring by a solenoid-actuated latch which is de-latched by the ignition system. In a second embodiment, the piston in a piston-type pump is driven by a solenoid plunger.
The remaining patents are of interest as showing the state of the art.